Cities unearthing best practices for compostable plastic
- September 13, 2013
- By Catherine Kavanaugh
Composting food waste is the next step for cities hungry to reach recycling goals and reroute organic matter back to the soil instead of landfills and incinerators.
Compostable plastics are making the job easier but there are challenges to overcome from manufacturers "greenwashing" products labels to composters determining what will breakdown in an appropriate time frame given the temperature and moisture of their facility.
As more cities start up food waste programs, Michele Young, organics manager of the San Jose's Environmental Services Department, says the time is ripe for an online clearinghouse of what works, or as she calls it, a compostable plastics toolkit.
Young wrote and received a $50,000 grant from the Urban Sustainability Directors Network (USDN) to pull together the best resources for city recycling coordinators and others wanting to successfully compost plastic bags, plates, bowls, utensils, coffee stirrers and other food service items.
"There is tremendous opportunity to capture more food waste with compostable plastics but the solid waste industry is working to bring end-of-life issues to light," Young says. "If the compostable plastics don't get to a large-scale composting facility, they can cause greater problems than conventional plastics."
For example, compostable plastic that ends up at a material recovery facility will only degrade the quality of the plastic commodity coming out of the recycling process.
"If you're making plastic straps to secure bricks on the back of a truck, you really don't want a disintegratable plastic in the recycled plastics mix," Young says. "That's a contaminant."
Young is working with colleagues in Ashville, N.C., and Gaithersburg, Md., to determine what the compostable plastics toolkit should have to support food waste diversion programs. The goal is to post the information on the U.S. Composting Council (USCC) website in February 2014 and then update it frequently.
"A lot of resources are floating in the ether," Young says. "We'll make them into a package so a municipal staff person with no background at all can see tools that are peer-reviewed or refer residents, businesses and compost operators to the toolbox."
Fueling the need
The number of compostable plastics making their way to consumers is outpacing development of the infrastructure to handle the products and that's causing problems for composting facilities and well-intentioned consumers.
Young says many compostable plastics end up in landfills because the buyers don't live in places with collection and processing programs.
"People want to do the right thing. They want to do the next green thing but we need to build all the pieces," Young says. "We can't say it's on the shelf; buy it and consider that green. We also have to ask what do the collection systems look like. Are there available composting facilities? How can consumers be sure they bought something that is truly compostable?"
While San Jose is a leader in solid waste management, the city is moving ahead cautiously with compostable plastics. The city spent five years creating a collection and processing system that diverts 300 tons of commercial food waste to two composting facilities every day. However, they aren't requiring use of compostable plastic bags or service ware yet.
"We're in the process of doing disintegration testing to identify materials that will disintegrate in our composting facilities," Young says
Portland, Ore., is further along with residential and commercial programs. New York City is adding high-rises and neighborhoods to its food waste pick-up program every few months. The state of Massachusetts plans to require all restaurants, universities, hospitals and hotels that generate at least a ton of organic materials every week to repurpose the food; composting is one of the options.
Food waste and organics make up 20-25% of the waste stream going to Massachusetts landfills and incinerators, state officials announced recently. They project the proposed ban on food waste disposal will help the state reach its goals to reduce the waste stream by 30% by 2020 and 80% by 2050.
The need to offer cities more resources came out of a meeting of the Compostable Plastics Task Force, which is an initiative started by the USCC. Cary Oshins, USCC spokesman, said the toolkit will be handy for decades as municipal leaders with a lot of questions and limited staff and budgets hammer away at issues.
"There's no reason to recreate the wheel," Oshins says. "It may be 50 years before Bismarck is composting, but many cities, especially major ones, are banning food waste and taking on the huge effort now. This toolkit will have fact sheets, planning guides, white papers and camera-ready material."
Oshins points to Cedar Grove in Washington, which recycles food and yard waste into compost for the Seattle area, as a model for a robust program.
"They say if you're going to do a food waste program and bring it to our facility, it needs to be approved by us," Oshins says. "So when the Seattle Mariners wanted to convert their stadium, they worked with Cedar Grove and their product suppliers to meet the end user's -- the composter's -- specifications. That's a great example of working through the value chain of resin manufacturers, product producers, distributors, the facility, and there's a hauler in there some place, to coordinate all the pieces for the system to work."
Getting it right
Cedar Grove composts 400,000 tons of organic matter annually from households, businesses, offices schools and prisons.
"The reason we take compostable products is to get more food waste because it's a good feedstock for our process. It brings in a higher nitrogen, which we need a lot of in the fall and winter and it really helps us maintain a consistent product year round," says Michele Riggs, the biodegradable technical specialist and environmental technician for Cedar Grove.
She and other staff test everything for disintegration rates in their composting process. Riggs says not all of the compostable materials certified by the Biodegradable Product Institute (BPI), which reviews products that meet standards of the American Society for Testing and Materials (ASTM), make the Cedar Grove list.
"The parameters in which we operate to create and manufacture our compost are extremely different than the parameters used in the methods to test these products for disintegration," she explains.
The Cedar Grove process takes 49-60 days, depending on the season and tonnage coming in. Part of the process entails pulling out materials that consumers thought were compostable, and even more so, traditional plastic.
"People don't realize the little tag you got with the plant for your garden doesn't go in your yard waste bin and we have more than a million customers so it really does add up over time," Riggs said.
People also don't realize labels can be deceiving with descriptions touting products or packaging as biobased, biodegradable, degradable, compostable, starch based, plant based, and made from "renewable" materials.
For consumers, Riggs suggests watching for the BPI certification logo even though it doesn't mean a product will turn to humus in 60 days or less at Cedar Grove.
"People need to know about identification so they aren't greenwashed," she says. "Many food service products are labeled 'biobased' or 'made from plants,' which means they are made from renewable sources and traditional polymer chains. People may associate that as green and part of 'clean green' and may place them with their yard waste and that's bad."
For example, the PlantBottles used for some Coca-Cola and DaSani products come from Brazilian sugar cane and molasses and are intended to be recycled and not composted.
Look for the logo
The BPI compostable logo, which shows an evergreen and leaf, indicates a product is certified to biodegrade completely, quickly and safely in a well-run or commercial compost facility as opposed to a back-yard compost bin. To carry the logo, products that meet ASTM D6400 standards for compostable plastic films and bags and D6868 standards for compostable fibers and plastic-coated paper and board must pass an independent BPI review.
Biodegradable doesn't equate to compostable. Biodegradable is a vague term without a time frame. A tree is biodegradable but it can take centuries while composting is a managed process with definitive temperatures and times to create humus, says Steve Mojo, BPI executive director.
"There are also requirements of how much has to biodegrade," he adds. "The person who put starch in the polypropylene can say its 50% starch so it's biodegradable but the other 50% will remain there forever" so it isn't compostable.
Mojo lauds California's progressive labeling law, which prohibits the use of the term biodegradable on all plastic products and mandates the term compostable only be used for products that meet the ASTM D6400 and 6868 standards.
BPI has licensed products from 140 companies since 2002 and recently went online with the largest public database of 3,300-plus compostable products for consumers and composters.
"It's something we have been working on for close to two years now," Mojo says. "The industry has grown dramatically. The material properties and the products have gotten remarkably better. I've been in the business for 20 years and I can say compostable materials are every bit as good as the traditional plastics and applications they are used in."
Still, Riggs has one lament amidst all the innovations: those little stickers on pieces of fruit.
"You don't pull off the fruit sticker and it ends up in our product and in the gardens of our customers," she says. "Most of them are okay with it compared to seeing forks and piece of plates. Even so, that's one of our big things. I'm really trying to find a compostable sticker. That's just another thing to tackle."
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